MATLAB: Vector index of consecutive gap (NaN) lengths

gap-filling

Hi
For a vector A with random, sometime consecutive gaps of NaN, I want to develop a vector B of same length A that will indicate the length of local consecutive gaps for every value in A. B would have zeros for non-NaN locations in A.
so for
A = [2 4 NaN 7 9 NaN NaN NaN 32 NaN NaN 8];
I'd get
B = [0 0 1 0 0 3 3 3 0 2 2 0];
Ideas? Speed is always a virtue.
Thanks!
Tom

Best Answer

And if you like Ryan's idea but don't like bwlabel because it's evil:
A = [2 4 NaN 7 9 NaN NaN NaN 32 NaN NaN 8];
CC= bwconncomp(isnan(A));
n = cellfun('prodofsize',CC.PixelIdxList);
b = zeros(size(A));
for ii = 1:CC.NumObjects
  b(CC.PixelIdxList{ii}) = n(ii);
end
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